Trap Quest is a fantastic transformation roguelike made by aika (a roguelike, for sissies not in the know, is generally a turn-based role-playing game with randomly generated levels and loot).

The development thread is at TFGames.

You've won a chance to play a new virtual reality game where you can win a fabulous cash prize. It's every gamer's dream—making money for playing a engrossing, realistic game.

Moments before you load into the game you're told that the effects in game will be changing your body in the real world. That doesn't sound terrible—albeit a bit dangerous and unexpected. It starts to seem a bit weird once the game starts and you find yourself in a room with a pink motif filled with a closet of girly things. You can't venture out and about naked though; so you decide to throw on the tube top and a pair of panties just for some semblance of modesty. But right after you put on the tube top you can't help but stand up straight and push your chest out...and for some reason you can't bring yourself to take it off. Curses!

Venturing further you stumble over a trip wire that brings down a tiny syringe that injects a strange fluid into your leg. Moments later you feel your nipples tingle and absent-mindedly wonder if your chest is looking a bit too poofy. A few rooms later, when you've accidentally activated a sprinkler that's changing your hair and making your face look more feminine and trying to fend off an animated blow-up doll trying to force its way into your ass, you wonder if you may be a bit over your head.

Hours later and you're strutting about in 6-inch heels, weakly trying to stave off thoughts of sex and submission. By now you've developed formidably sized breasts and are wearing a provocative outfit consisting of a skimpy dress, overly tight bra and a string of a thong—just so you can try to ward off the next fiendish sex-crazed monster you see. You've already passed out once and briefly awoke in the real world to see that your body has indeed changed and your figure in the outside world is becoming girlier and more sexualized. No matter, all you have to do is reach the exit before your mind breaks under the humiliation and constant stream of sex-crazed monsters, slutification and feminizing traps...

Now that doesn't sound too terrible, does it?

The game runs in Gargoyle (an interactive fiction engine that uses text-based input—but don't worry, there's plenty of pictures for you more visually oriented sissies). There's also a wiki to help you out (if you want to know a quick list of commands).

It's a fantastic game that has surprisingly tight focus on sex while still maintaining a semblance of gameplay with actual goals (even if it doesn't have an ending as of Release 6. So if you're interested in vicariously living out your fantasies of being trapped in a world where everything is out to feminize you and turn you into a slut while questing for your freedom and safety (yeah, I think we know that's not happening, sissy), then you will likely enjoy Trap Quest.